The allergens of Epicoccum nigrum Link. I. Identification of the allergens by immunoblotting.

Two atmospheric isolates of Epicoccum nigrum (EN) were grown under sporulation conditions. Dialyzed extracts of spores, (greater than 95% pure) and pure mycelia were used for skin testing, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and immunoblotting. By skin testing, 49 of the 126 atopic patients were found to be sensitive to EN in St. Louis, Mo., and Corpus Christi, Texas, combined. On immunoblotting, which was performed on 17 sera, 44 bands (12.3 to 119.0 kd) were detected; six were unique to spore, four were unique to mycelium, and 34 were common to both. No single band bound IgE from all sera. The most frequent band corresponding to 42 kd occurred in 11 sera. Five other bands were recognized by more than one half, whereas the remainder bound fewer sera. All skin test-positive patients had positive immunoblots; the number of bands recognized varied from three to 25. Spore or mycelium-specific, as well as common bands were recognized by 13 of 17 sera. Two sera recognized only spore and mycelium-specific bands. Only spore-specific bands were bound by two sera. No strain differences were detected. The binding patterns were comparable in the sera from both St. Louis, Mo., and Corpus Christi, Texas. These data suggest that EN is a significant allergen in urban communities. Allergenic proteins occur in both spore and mycelium, suggesting that both must be included in the reagents for skin testing and immunotherapy.

Grass aeropollen of the western United States Gulf Coast.

Volumetric air sampling was performed at Corpus Christi, Tex., September 1987 to August 1989. Grass aeropollen during all of 1988 accounted for 15.3% of total pollen captured during two major peaks, one in May and another during September and October. The remaining grass pollen, about one-quarter of the total, was found throughout the year with low levels in the winter and mid-summer. This bimodal pollen release corresponds to the flowering of two major types of grasses occurring in the western Gulf Coast region, the cool temperate species which are predominantly spring flowering in response to long-day photoperiodicity, and the more common warm temperate and subtropical species flowering by and large in the fall as short-day plants. Supplementing the already rich grass flora and adding to the high proportion of total aeropollen was the long distance dispersal of grass pollen found perhaps in sufficiently high quantities to trigger allergic symptoms and to cause grass pollinosis out of season, at least in acutely sensitive individuals. This occurred in late March, well before the spring peak in May. Correlations existed between near-drought conditions and reduced pollen shed in 1988, and normal precipitation and much higher pollen shed during parts of 1987 and 1989, illustrating the importance of environmental factors such as moisture on annual pollen frequency and level of pollinosis which can be variable and annually unpredictable. What is predictable is the genetically controlled timing of pollen maturation and release which will be generally the same year by year.(ABSTRACT TRUNCATED AT 250 WORDS)

Asteraceae aeropollen of the western United States Gulf Coast.

Volumetric air sampling was performed near Corpus Christi, Texas during 1988 and supplemented with data from 1987 and 1989. Frequencies of captured pollen grains of Parthenium hysterophorus, Ambrosia and allied genera, Helianthus, and other Asteracea were examined. Asteraceous aerospora in 1988 accounted for 22.1% of all pollen found, of which 83.4% were pollen of Ambrosia, 12.4% of Parthenium, and the remainder (4.1%) representative of other genera. Capture of native Ambrosia species and P. hysterophorus peaked in September and October in 1987 and 1988, but Parthenium pollen was also found year round with a smaller secondary peak during May, 1988 and 1989. In the winter a different Ambrosia pollen was captured which compared with A. hispida found in the Yucatan Peninsula and southern Florida at a time when no ragweed was flowering in the vicinity of Corpus Christi. Such a pollen capture probably represents long distance dispersal (ca. 600 miles, 965 km) on strong easterly to southerly prevailing winds. Pollen capture occurred most frequently during daylight hours when percent relative humidity was lower and near midnight when inversions occur. Comparison of pollen capture with meteorologic data demonstrated that photoperiodic responses probably account for the initiation and termination of Ambrosia flowering, and to some extent that of Parthenium, and not sharply lowered temperatures or frost for ending pollen release. Previous plant surveys have shown that P. hysterophorus is more common in the Corpus Christi area than species of Ambrosia, or any other Asteraceae, even though ragweed pollen capture proved 6.9 times greater. This disparity is most likely due to limited long distance dispersal of Parthenium pollen, less pollen produced per another, and a less developed mechanism of wind pollination (passive dispersal or amphiphilous). Since both Parthenium and Ambrosia are significant allergenic plants, correlations between airborne pollen of Parthenium and allergic potential suggest that a prolonged pollination season and perhaps increased allergenicity of unique Parthenium pollen proteins allow Parthenium to be a major allergen despite significantly less ambient pollen.

Aeropollen of weeds of the western United States Gulf Coast.

Volumetric air sampling was performed near Corpus Christi, Texas during all of 1988. The most significant weeds releasing airborne pollen, besides the Asteraceae, were the Amaranthaceae and Chenopodiaceae at 14.8% of total pollen captured, which peaked in September and October. Greater pollen capture (74%) occurred from a peak at 11 PM at a time when inversions are frequent to 9 AM than during the period from late morning to 9 PM. Frequency of amaranth-chenopod pollen capture in the western Gulf Coast region showed no relationship with frequencies along the northern and eastern Gulf Coast nor in eastern North America generally, but rather with western North America where these grains have also been sampled at high levels. As in the West, therefore, amaranth-chenopod aeropollen is sufficiently frequent to be a major source of allergens in the western Gulf Coast region. Other weedy plants, Cannabis/Humulus, Rumex, and the Urticaceae (Parieteria/Urtica) each account for only about 1% of the total annual pollen shed, and consequently they are not nearly as potentially relevant here in pollinosis as are the amaranth-chenopods and Asteraceae. Plantago pollen is very infrequently sampled (less than 0.1%) even though several species are common in the area. Acalypha is newly reported as releasing airborne pollen, a genus related to Mercurialis known to release allergenic pollen in Europe.

Distribution and incidence of North American pollen aeroallergens.

Using standardized aerosampling procedures, ambient pollen samples were collected at 15 locations in six regions of North America. The results provide baselines for examining human exposure to inhalant pollen allergens throughout the year on a broad geographic scale. In eastern temperate areas, pollen shed was closely linked to plant flowering seasons, with trees releasing pollen in the spring, grasses in the early summer, and weeds in the later summer and fall. Variations to this fundamental pattern were observed to the south and west; understanding these differences is essential if atopic persons suffering from allergic symptoms are to be assisted. For example, highly diverse tree pollen was found in North Carolina and Georgia for prolonged periods at high levels. These data suggest that a more sensitized population in the southeastern United States manifests allergic symptoms longer. Further south and southwest, pollen was captured throughout the year and sometimes at unexpected times. For instance, bimodal releases of grass pollen in both the spring and fall allow dual exposures of atopic persons, extending possible hypersensitivity to multiple seasons. Enhancing pollen exposure further, our data show limited overall variation in morning and afternoon levels, implying a continuous absorption of all major pollen types during daylight hours.